function enable_smooth_scroll() {
    function filterPath(string) {
        return string
                .replace(/^\//, '')
                .replace(/(index|default).[a-zA-Z]{3,4}$/, '')
                .replace(/\/$/, '');
    }

    var locationPath = filterPath(location.pathname);

    var scrollElement = 'html, body';
    $('html, body').each(function() {
        var initScrollTop = $(this).attr('scrollTop');
        $(this).attr('scrollTop', initScrollTop + 1);
        if ($(this).attr('scrollTop') == initScrollTop + 1) {
            scrollElement = this.nodeName.toLowerCase();
            $(this).attr('scrollTop', initScrollTop);
            return false;
        }
    });

    $('a[href*=#]').each(function() {
        var thisPath = filterPath(this.pathname) || locationPath;
        if (locationPath == thisPath
                && (location.hostname == this.hostname || !this.hostname)
                && this.hash.replace(/#/, '')
            ) {
            if ($(this.hash).length) {
                $(this).click(function(event) {
                    var targetOffset = $(this.hash).offset().top;
                    var target = this.hash;
                    event.preventDefault();
                    $(scrollElement).animate(
                            { scrollTop: targetOffset },
                            500,
                            function() {
                                location.hash = target;
                            });
                });
            }
        }
    });
}
jQuery.fn.topLink = function(settings) {
    settings = jQuery.extend({
        min: 1,
        fadeSpeed: 200,
        ieOffset: 50
    }, settings);
    return this.each(function() {
        //listen for scroll
        var el = $(this);
        el.css('display', 'none'); //in case the user forgot
        $(window).scroll(function() {
            //stupid IE hack
            if (!jQuery.support.hrefNormalized) {
                el.css({
                    'position': 'absolute',
                    'top': $(window).scrollTop() + $(window).height() - settings.ieOffset
                });
            }
            if ($(window).scrollTop() >= settings.min) {
                el.fadeIn(settings.fadeSpeed);
            }
            else {
                el.fadeOut(settings.fadeSpeed);
            }
        });
    });
};